Analysis of fertilizer

This Presentation is all about classification and chemical analysis of NPK Fertilizers

1. Analysis Of Fertilizer 1 Dr. P. L. Kishore M.Sc ., B.Ed., PhD., APSET Guest Faculty School of Chemistry Andhra University

2. What is a Fertilizer ?? 2

3. Any material applied to a soil or plant to supply essential elements is called Fertilizer What are some different types of fertilizer? ▸Mineral ▸Organic ▸Inorganic 3

4. Mineral Fertilizer ▸Simply ground rocks containing nutrients ▸Example: Dolomite lime provides calcium and magnesium ▸Usefulness is limited as they dissolve very slowly 4

5. Analysis of Fertilizer Organic Fertilizers Crop Rotation Animal Manures Sewage Sludge Septage Compost Municipal, food processing and industrial organic residues; usually dumped in landfills and ocean; much potential for composting Peat Partly decayed vegetable matter 5

6. Analysis of Fertilizer Inorganic Fertilizer Chemical fertilizers Made by industry Some are mined, others completely manufactured High nutrient content, therefore less expensive 6

7. Analysis of Fertilizer Typical fertilizer looks like…… Urea Crystals Ammonium Sulphate Urea Granuels 7

8. What plant needs??? 8

9. Nitrogen Fertilizers Ammonium Sulfate Anhyd . Ammonia Urea Nitrate of Soda Ammonium Phosphorus Calcium Cynamide 9

10. Common Phosphorus Fertilizers Di-Ammonium Phosphate Superphosphate (16-20%) MonoAmmonium Phosphate Bone Meal - made from grinding bones Manure 10

11. Potassium Fertilizers Muriate of potash ( KCl ) -60% potash, accounts for 97% of all potassium fertilizers Costs less and dissolves easily in water Nitrate of potash (KNO 3 ) -44% potash and 13% Nitrogen, common for container plants 11

12. Why NPK Fertilizer ?? Fertilizers provide three primary nutrients: Nitrogen (N) , Phosphorus (P) and Potassium (K) . Nitrogen supports vegetative growth. Phosphorus improves roots and flowering. Potassium strengthens resistance to environmental assaults, from extreme temperatures to pest attacks 12

13. Analysis of Fertilizer Analysis of fertilizer means finding the elements in the bag and their percent content. 13

14. Total nitrogen Kjeldahl method This test method is applicable to fertilizers containing no nitrate nitrogen. Urea is a common source of nitrogen in all solid nitrogenous fertilizers and it is widely used as a nitrogen release fertilizer. Urea decomposes when applied to the soil due to the activity of the enzyme urease . In presence of soil moisture and enzyme, urea normally hydrolyzes and converts to NH 4 + and CO 2 CO(NH 2 ) 2 + H 2 O + [urease] → 2 NH 3 +CO 2 14

15. Total nitrogen Kjeldahl method 15

16. The method consists of heating a sample at 360–410°C with concentrated  sulfuric acid (H 2 SO 4 ), which decomposes ("digests") the organic sample by oxidation to liberate the reduced nitrogen as ammonium sulfate . Catalysts like selenium, Hg 2 SO 4  or CuSO 4  are added to speed up the digestion. Na 2 SO 4  is also added to increase the boiling point of H 2 SO 4 . Digestion is complete when the liquor clarifies with the release of fumes 16

17. The end of the condenser is dipped into a known volume of standard acid (i.e. acid of known concentration) like HCl , H 2 SO 4  or some other strong acid. The sample solution is then distilled with a small amount of sodium hydroxide ( NaOH ) NaOH reacts the ammonium (NH 4 + ) to ammonia (NH 3 ), which boils off the sample solution. Ammonia bubbles through the standard acid solution and reacts back to ammonium salts with acid. 17

18. Ammonium ion concentration in the acid solution, and thus the amount of nitrogen in the sample, is measured via titration.  Strong base of known concentration (like NaOH ) is used to neutralize the standard HCl which was left after the reaction with NH 3 . In this case, the amount of ammonia is calculated by taking the difference between the amount of HCl added and HCl leftover. This method of titration is called Back titration method. 18

19. where: A = ml of standard acid (0.1M HCl ) taken to receive ammonia; B = ml of standard alkali (0.1M NaOH ) used in titration; W = weight of the sample taken; C = ml of standard alkali used in the blank. 1 ml 0.1M HCl = 0.0014 g N 19

20. Analysis of Fertilizer Ammoniacal plus nitrate-nitrogen by the distillation method Devarda’s alloy (50 percent Cu, 45 percent Al, and 5 percent Zn) reduces NO 3 to NH 4 in an alkaline condition. The method is same as for NH 4 -N estimation (above), except that 2–3 g of Devarda’s alloy is added before distillation in order to take into account the NO 3 by reducing it to ammonia form. 20

21. Analysis of Fertilizer Determination of Phosphorous Phosphate is generally present as bound with Ca as monocalcium phosphate, dicalcium phosphate and tricalcium phosphate. Monocalcium phosphate is in water soluble form, is considered available, while dicalcium phosphate becomes available in slightly acidic situations. Tricalcium phosphate is in an unavailable form and can be available only in acidic situations. 21

22. Pipette 5-–25 ml of aliquot (sample solution) depending on the P content in a 250 ml beaker, and dilute to 100 ml with distilled water. Add about 5–-10 ml of concentrated HNO 3 and about 10 g of ammonium nitrate. Heat this mixture on a water-bath at 55-–60 °C for 10 minutes. Add 3 percent ammonium molybdate solution in the beaker drop by drop with the help of a burette. Continue stirring with a glass rod until about 50 ml of molybdate solution is added. Stir for another few minutes until the yellow precipitate appears to become granular. 22

23. Cover the beaker with glass and allow it to settle for some time. Decant the clear solution through No. 44 filter paper, and wash the precipitate with 2 percent sodium nitrate solution, agitate thoroughly, and allow the precipitate to settle. Transfer the precipitate and filter paper to a beaker, and add 10 ml of 0.1M NaOH at a time by pipette until the precipitate becomes soluble. Add 1-–2 drops of 1 percent phenolphthalein, and titrate the excess of alkali against 0.1M sulphuric acid. Run a reagent blank with each batch. 23

24. H 3 PO 4 + 21HNO 3 + 12(NH 4 ) 2 MoO 4 = (NH 4 ) 3 PO 4 .12MoO 3 + 21NH 4 NO 3 2[(NH 4 ) 3 PO 4 .12MoO 3 ] + 46NaOH = 2(NH 4 ) 2 HPO 4 + (NH 4 ) 2 MoO 4 + 28Na 2 MoO 4 + 22H 2 O 24

25. 25 The calculation is as follows: 23 g equivalent of NaOH = 31 g P = 71 g P 2 O 5 (P × 2.29 = P 2 O 5 )

26. Determination of Potassium In all potassium fertilizers, K is generally present in water-soluble form. Therefore, it is estimated directly in fertilizer solution either gravimetrically, volumetrically or flame photometrically . In manures and organic fertilizers, wet digestion with acid is required prior to determination of K in order to bring the element into solution by digestion. 26

27. STPB method Potassium from the fertilizer sample is first extracted with water or ammonium oxalate. The K in extracted solution is precipitated with an excess of STPB as potassium tetraphenyl boron. The excess of STPB is backtitrated with benzalkonium chloride (BAC) or quaternary ammonium chloride using Clayton yellow as indicator: 27

28. The procedure is: 1. Extraction/preparation of sample solution: Dissolve a known weight (2.5 g) of straight K fertilizer in 200 ml of distilled water, and make the volume up to 250 ml for estimation. For NPK complex fertilizers or NPK fertilizer mixtures, dissolve the sample in 125 ml of water, add 50 ml of 4 percent ammonium oxalate solution, and boil for 30 minutes; after cooling, filter through dry No. 12 filter paper, and make the volume up to 250 ml for further estimation. 2. Transfer 15 ml of aliquot of sample solution to a 100 ml volumetric flask and add 2 ml of 20 percent NaOH and 5 ml of HCHO. 3. Add 1 ml of standard STPB solution for each 1 percent of K 2 O expected in the sample plus an additional 8 ml in excess in order to ensure complete precipitation. 28

29. 4. Dilute to volume (100 ml) with water, mix thoroughly, let it stand for 5–-10 minutes, and pass it through No. 12 filter paper (or equivalent). 5. Transfer 50 ml of filtrate to a 250 ml Erlenmeyer flask, add 6-–8 drops of Clayton yellow indicator, and titrate excess STPB with standard BAC solution to pink end point. The calculation is: where, f = % K 2 O/ml of STPB solution. This factor applies to all fertilizers where 2.5 g of sample is diluted to 250 ml, and 15 ml of aliquot is taken for analysis. To express the results as K rather than K 2 O, substitute 28.73 for 34.61 in calculating the value of f . 29

30. 30 Na[B(C 6 H 5 ) 4 ] + K + = K[B(C 6 H 5 ) 4 ] [C 6 H 5 CH 2 N(CH 3 ) 2 R]Cl + Na[B(C 6 H 5 ) 4 ] = [C 6 H 5 CH 2 N(CH 3 ) 2 R][B(C 6 H 5 ) 4 ] + NaCl

31. 31 THANK YOU